The Anatomy of Bypassed Low Resistivity Low Contrast HydrocarbonReservoirs: The Arts of Finding Additional Barrels in a Highly ComplexStratigraphic Geological Setting

摘要

Maximizing production and sustaining the barrels produced is the aspiration to all oil and gas key players.Current producing reservoirs may not giving good yield till the end of expected production life due todepletion,high water cut and also due to well integrity issues.Finding prolific reservoirs with thick payzones and excellent rock quality are also becoming scarcer as more complex reservoir characterizationcomes into play.The challenges are further compounded by high uncertainty in distinguishing hydrocarbonfluid type.Hence,a systematic effort need to be garnered to sustain the production pipeline.This paperwill present several case studies and petrophysical solutions in monetizing the untapped low resistivity lowcontrast reservoirs in a highly complex stratigraphic trap geological setting to squeeze more barrels intoproduction as well as adding value to the reserves portfolio.Identifying the low resistivity and low contrast (LRLC) reservoirs starts with delineating the log responsescomplemented by other subsurface data such as mud log,cores,fluid samples and advanced acoustic loggingto determine lateral sand continuity.Often,well test and production data is used as the benchmark toidentify hydrocarbon fluid type in the contradicting evidences.Comparison of nearby wells performanceand evaluating fluid contact movement will be also part of the assessment stage.Application of in-housereservoir enhancement modeling (REM) will be the highlight of this paper to reveal those new promisingreserves which are masked by thin laminated sand,low salinity,presence of light oil with similar logresponses as gas and high silt content.Few examples relating the well production performance with logcharacteristics will be also discussed in this paper.Results proved that production gain has soared up to 4800 bopd in total to make an astoundingimpact to the overall field production scenario.In few cases,significant new reserves addition is recordedwhich further open-up new upside opportunities for work-over,more aggressive production enhancement,appraisal and development drilling campaign.A systematic formation evaluation and petrophysicalworkflow has also been established to mature and realize the gain which sets a replication standard to theentire region.As more data comes in from the actual jobs done,a database relating the log responses withproduction capacity and catalogue of past job lessons learned have been initiated for future reference anddemonstrating concrete evidences in realizing LRLC potential.In a nutshell,exploiting LRLC potential in complex stratigraphic play requires an intensive subsurfaceevaluation and offers a promising opportunity in expanding the resource base and generating the cash.Theefforts must continue with more success being replicated and bringing in more technology to minimizeLRLC uncertainty and create a chain impact to production growth.